Should I tweak my titles and descriptions to improve my CTR?

Matt's answer:
CUTTS: A question from Bangalore. Amalve asks, “Do title and description tags, are they helpful to increase the organic Click-Through Rate which will in turn help with better rankings with a personalized search perspective?” Great question. So many people think about rankings and then stop right there. And that’s not the right way to think about things. You want to think about rankings and then you want to think about maximizing your Click Through, which means making your title and your snippet very, very compelling. Not deceptive, but something that invites the users to click on it because they know they’ll find what they want. And then you want to think about conversion rates and you want to get good ROI. And so, title and description tags absolutely can increase your organic Click-Through Rates. Try to optimize for that because it doesn’t really matter how often you show up. It matters how often you get clicked-on and then how often you take those clicked on visits and convert those to whatever you really want; sales, purchases, subscriptions, whatever it is you’re trying to optimize for. So, I wouldn’t think about it in terms of, “Oh yeah, I get more visitors,” and it helps me in terms of personalize search. Just think about it in terms of if I get more visitors and they can work better. So do spend some time looking at your title, looking at your URL, looking at your snippet that Google generates and see if you can find ways to improve that and make it better for users because then they’re more likely to click. You’ll get more visitors; you’ll get better return on your investment.
by Matt Cutts - Google's Head of Search Quality Team